What is the expected output? What do you see instead?
Intermittently the loot frame will fail to appear on a gather. The cast bar for the gather shows up, and I get XP for gathering the node, my character remains kneeling in the "looting" position, but the loot frame never appears with the contents. The problem is rare, but once it occurs, it will reliably continue to happen on repeated attempts to gather the same or different nodes. Once it gets into that state, the only way I've found to "unstick" it is either /reloadui or go kill a mob and loot it, which appears to restore the loot frame to normal operations.

Still happening in z12b-release, still very annoying. This time it happened while gathering an awkwardly-placed piece of the isle chamberlain, and wasted several minutes un-glitching it so i could gather my item.